CD motor conversion

[morairamike]

I have a Hornby 9F (UK built) tender drive. I bought it off eBay quite a few years ago and at the same time bought a 5 pole direct replacement armature. That I fitted and I also fitted a DCC Concepts decoder with stay alive capacitor. After fitting the 5 pole it ran quite well but not perfectly, still a bit jerky at slow speed.

So I decided to weeks ago to buy a Strathpeffer Junction CD motor conversion kit. Today, as it's raining outside, I decided to fit it. The conversion was straight forward and all went well. When tested the loco runs much smoother than it did and the start voltage has been reduced to 10 from 17 on 128 steps.

Excellent bit of kit and we'll worth the money.

[ColinB]

I converted my old ringfield locos to 5 pole motors, well the ones where it was easy. I never did get the DCC concepts dcc decoders to work that well, I found that the Zimo £20 ones worked so much better. I found that for some reason the DCC concepts decoders seem to have issues with current limits, the Zimo had a better specification. In the end I found all my old Ringfield based bodies would fit the new Hornby chassis, so that is what I did. It is nice to know though that the CD conversion kit works well, I read so many contradictory posts.

[morairamike]

Good feedback thanks.

Even with a stay alive the loco would stop start and run jerkily. With the same initial setting the CD motor ran smoothly. Only CV changed was 29 to change direction and SV reduced from 17 to 10. The whole mechanism is much smoother.

[DonnyRailMan]

For anyone thinking of doing this conversion Sam of Sams Trains on Youtube has done a video showing how to do it step-by-step.

[The son of Triangman]

CD conversions tend to be used as a bodge instead of repairing or servicing a ringfield motor. The humble 3 pole or 5 pole ringfield motor is a good motor if looked after properly, that means good servicing and repair when needed. A thing to bear in mind is that conversion also tends to devalue a model when it comes time to sell to the general market as the model is no longer in original condition.

However if you decide that a CD motor is the way you want to go, then making a CD motor DCC isn't rocket science and is within the abilities of most here, even without youtube tutorials. Matching the right decoder to the CD motor is more difficult as a previous poster here has found.

[96RAF]

These conversions work better if the motor is 12v, many are 6v or even 3v and thus require diode packs to drop the applied voltage to a safe level. As said some decoders can have CV5 (max chat) and CV6 (mid range) values adjusted to suit.

[Hipwell]

My old HST without additional pickups runs so smoothly you would not believe it was 30 years old.

It's got a strathpeffer junction cd conversion. I thought it was the 6v model but I'm now thinking it might be a 12v because I run it on full chat quite often with no voltage droppers and it runs perfectly fine.

[Flashbang]

I looked into these conversions a couple of years ago, They look really good, if you're able to undertake the conversion process.

However, I was totally disappointed by tender drive locos, as often the locos wheels and motion would lock up and all you saw was a loco skidding along the rails as the locos wheels didn't turn and the tender drive pushed the loco along.frowning

Sold most of them, and now I only purchase modern loco drive items!

But the conversion would be great for a Diesel or other non tender drive items. smiley

[DonnyRailMan]

Link here to CD motor conversion

[96RAF]

My cheapskate HST CD motor conversion was simply remove the ring-field motor innards, chop a suitable length ring from a cardboard tube of the right diameter and glue the CD motor inside the ring, then the ring inside the ring-field housing. The ring length depends upon if you are using the regular width or the slim width CD motor. Connect decoder motor feed wires to the CD motor as per normal. There is no need to isolate the ring-field motor housing per a conventional conversion as the CD motor is totally isolated by my cardboard ring. The cardboard tube was free from Lidl greengrocery department, where it is used as a core for the plastic bags you pack your veg in.

[DonnyRailMan]

just come across this conversion kit.

info@strathpefferjunction.com

[morairamike]

DonnyRailMan that's the one I bought. Extremely pleased with it. Had my 9F running without stock yesterday at speed setting 1 of 128.

[Cathurga]

Glad to see others have successfully done this conversion, as I have two of the Strathpeffer kits winging their way to me now. One is going to go into the tender of a Stanier 8F loco and the other is going to a horrendous Class 37 diesel that should be thrown away, but its great for the kids to use and with the conversion and a decoder, the cost will be a lot less than buying a 'sacrificial' loco.

So, my question, as others have pointed out, is what decoder to get. My plan was to see what sort of amp draw these motors give. I am assuming the motors being sent to me with the kits are the slim 6V ones, so less volts is going to require more amps....

I have sent my Select Controller away for FW upgrading and I understand (open to correction) that I will be able to adjust CV values in order to ensure the loco's dont go as high as 'warp' speed or 'ludicrous speed' (Spaceball's reference).

What decoder did you use Mike?

With regards to tender drive loco's having the wheels slipping on the loco, surely it would be doing that regardless of what type of motor was driving it? All things being equal, as long as the wheels and linkages are all lubed and not bent, surely this is independent of the drive function? or am I missing something obvious?

[96RAF]

Your updated Select will now allow changing CVs - ref the user manual addendum as you need both the basic manual and the add on.

CV5 taming is decoder dependant e.g. Hornby R8249 basic decoder does not support changing CV2 (Vstart), CV5 (Vmax) or CV6 (Vmid).

You need the slim motor for Co-Co diesels or most steamer tender drives. The wide motor fouls the adjacent wheel set on these locos and is only really suitable for some non tender (e.g. 0-6-0) locos or Bo-Bo diesels.

[Cathurga]

Thanks chap, I was going to exclude Hornby as although the seem good in a DCC ready environment, they don't always play nice in hardwired environments...or so I've read. Mike suggested DCC concepts and I see the Dapol ones seem to be high amp capable, will be doing some research.

[morairamike]

Yes it DCC Concepts with stay alive.

[Fishmanoz]

Just on plugging in a Hornby decoder to a socket versus hardwiring it - there will be no difference whatsoever. And where there is room, it is better practice to first wire in a socket before plugging the decoder in to it.

Might you be referring to the fact that some older non-DCC Ready locos don’t run so well on DCC, or may need a higher power decoder than an 8249, or need more complicated conversion to ensure motor isolation from the wheels and pickups? Not if you first ensure it is running well on DC (if not, it is most unlikely to on DCC), follow the correct conversion instructions and ensure the decoder chosen will handle the motor current draw.

On other decoder brands, there’s any number of topics here with opinions and experience with other brands, a lot more than just DCC Concepts and Dapol.

[Cathurga]

Fishman, yes that's kind of what I meant. The Hornby decoders seem to play nicely with a loco that's been designed from the ground up to be DCC run. Converting ringfield/XO etc typ locos have some pitfalls, mainly related to amp draw, chassis isolation and ease of conversion.

Lais, AE, Zen, Hornby etc etc all with their own idiosyncrasies

.....

[The son of Triangman]

X.O motors are very easy to convert.